1. Field of the Invention
The present invention relates to a locking apparatus for a drawer type circuit breaker.
2. Prior Art
An electrical connection between the controller and switchboard of a drawer type circuit breaker is established either by a terminal board, plug-to-plug connection, or automatic connection device. The automatic connection device is the best of these three alternatives but is relatively expensive and therefore the terminal type or plug-to-plug type is used more often. Plug type circuit breakers are particularly easy to connect and disconnect.
The plugs of the conventional plug-to-plug type circuit breaker can be connected and disconnected in any one of three positions; a disconnect position where the plug is not inserted into the controller, a test position where the plug is inserted into the controller, and an operation position where the main terminals of the circuit breaker and the fixed terminals are closed. For example, if the plug is accidentally disconnected while in the operation position, excessive current will not be interrupted.